The relationship between the synthase D to I conversion and the dephosphorylation of the two primary phosphorylation sites of skeletal muscle glycogen synthase will be assessed using 1000-fold purified phosphoprotein phosphatase. The correlation between dephosphorylation and D to I conversion will be determined using 32P-synthase labeled in both sites. This will allow us to determine the role of these two sites in the regulation of synthase activation by dephosphorylation. The CNBr 32P-peptide containing the "trypsin-insensitive" site from synthase phosphorylated using cAMP-dependent synthase kinase will be purified. The amino acid sequence around the 32P-serine residue will be determined. The CNBr 32P-peptides from liver synthase will be analyzed. The liver synthase will be phosphorylated using either cAMP-dependent or cAMP-independent synthase kinases. The numbers of CNBr 32P-peptides, their relationships, and temporal rates of phosphorylation will be determined.